Optimizing the expression of recombinant alphabetagamma GABAA receptors in HEK293 cells for high-throughput screening

Despite being important clinical targets, it is not straightforward to reliably express recombinant trimeric alphabetagamma GABA-A receptors (GABA(A)Rs) for high-throughput screening. This study therefore sought to devise a simple and reliable means of transiently expressing alpha1beta1gamma1 and alpha1beta1gamma2 GABA(A)Rs in HEK293 cells. Expression efficiencies resulting from 5 different transfection strategies were assessed by flow cytometry and pharmacological analysis using an anion-sensitive yellow fluorescent protein-based assay. PolyFect and Effectene, employed according to the manufacturers' instructions, conferred the strongest and most reliable expression of trimeric alphabetagamma GABA(A)Rs. Functional analysis via the yellow fluorescent protein assay revealed dramatic differences in the pharmacological properties of gamma1- and gamma2-containing receptors, consistent with previous electrophysiological characterizations. The authors conclude that this method of expressing and screening recombinant GABA(A)Rs provides an effective means of discovering novel GABA(A)R modulators for use as therapeutic lead compounds and pharmacological probes.